Adsorption Behavior of Sr(II) and some Typical Co-existent Metals Contained in High Level Liquid Waste onto a Modified Macroporous Silica-Based Polymeric DtBuCH18C6 Composite

摘要

To significantly reduce the bleeding of 4,4',(5')-di(tert-butylcyclohexano)-18-crown- 6 (DtBuCH18C6), an improved novel macroporous silica-based polymeric composite (DtBuCH18C6+TBP)/SiO2-P was synthesized. It was performed by impregnating and immobilizing DtBuCH18C6 into the pores of the SiO2-P particles via the molecular modification of DtBuCH18C6 with a tri-n-butyl phosphate (TBP) through hydrogen bonding. The adsorption of a few typical simulated fission and non-fission products Pd(II), La(III), Na(I), K(I), Sr(II), Ba(II), Ru(III), Cs(I), Mo(VI), and Y(III) onto (DtBuCH18C6+TBP)/ SiO2-P was investigated at 323 K. It was done by examining the effect of contact time and the HNO3 concentration in a range of 0.1-5.0 M. Sr(II), one of the main heat emitting nuclides, showed optimum adsorption onto (DtBuCH18C6+TBP)/SiO2-P in 2.0 HNO3, while others showed very weak or almost no adsorption except a portion of Ba(II). The leaching of TBP and DtBuCH18C6 from (DtBuCH18C6+TBP)/SiO2-P was evaluated. The average content of DtBuCH18C6, 298.7ppm, leached from (DtBuCH18C6+TBP)/ SiO2-P in 2.0 M HNO3 at 323 K was obviously lower than that of 797.3 ppm leached from DtBuCH18C6/SiO2-P at 298 K. The significant reduction of DtBuCH18C6 leaching from its macroporous silica-based polymeric adsorbent was achieved. It is useful for the recycle operation of the silica-based DtBuCH18C6 impregnated polymeric composite in chromatographic partitioning of Sr(II) from high level liquid waste (HLLW).